Lindsay Lohan may have a stepsister she never knew about!

New York, June 28 : Just when Lindsay Lohan thought that her life was back on track, she's back in the spotlight and this time it's the actress' father who is to be blamed.

According to reports, the 'Mean Girl' star may have a secret sibling from dad Michael's extra-martial tryst.

A woman who says she had an affair with the actress' dad, Michael, claims they had a love child who is now 13 years old, reports OK! magazine.

"I don't know if she's mine. I've seen pictures and, to tell the truth, there are similarities with Linds," the New York Daily News quoted Michael, as saying.

Michael Lohan identified the woman as Christy Horn and said the little girl is named Ashley. They live part of the time in Montana, he said.

"She said she believed the child was mine and stated that I was the only man she was with. I find it hard to believe because she has had three other relationships since that time and is going through another divorce now," he added.

Michael Lohan, who is divorced from Lindsay's mother, Dina, said he met the mystery woman in Houston, Tex. in 1982.

"I did not have an affair with Christy Horn. In 1995, while I was separated from Dina, I was contacted by Christy as she was living in New York and going through a divorce. I met with Christy and I was with her," he explained.

Lindsay's dad said they corresponded while he was in jail for drunk driving.

"She said she had a paternity test with her ex-husband and it was negative," he said.

Michael Lohan said he's willing to take a paternity test.

"I will do what's necessary to find out the truth and handle the matter as I should," he said.

But he doubts that Ashley is his and suggested Horn might be looking for a payout.

ANI